Rethinking Xylenes Production via Toluene Methylation

Rethinking Xylenes Production

via Toluene Methylation

GTC Technology

Joseph C. Gentry – Director, Global Licensing

IOCL Petrochemical Conclave – New Delhi – February 7, 2014

Re-thinking Xylenes

CH3

CH3

Intermediate for polyester manufacture

Among fastest-growing petrochemicals

Para-dimethylbenzene (PX)

PX Manufacturing

• Overview of paraxylene production, with benzene

by-product

PX Manufacturing


by-product

• Conventional processes do not address the

fundamental problem of methyl group shortage

PX Manufacturing


by-product

• Conventional processes do not address the

fundamental problem of methyl group shortage

• GT-TolAlksm is the unique technical solution to

maximize PX production from mixed aromatics

Aromatics

Extraction

Toluene

Conversion

Benzene C

olu

mn

Tolu

ene C

olu

mn

Xyle

ne C

olu

mn

BenzeneC6 -C7 raffinate

C9+

Paraxylene

Hydrotreated

Naphtha

Xylene

Isomerization

Catalytic

Reformer

C5

Xyle

ne C

olu

mn

C9+

Refo

rmate

Split

ter

Dehepta

niz

er

Paraxylene

Recovery

Typical Aromatics Complex for PX

Aromatics

Extraction

Toluene

Conversion

Benzene C

olu

mn

Tolu

ene C

olu

mn

Xyle

ne C

olu

mn


C9+

Paraxylene

Hydrotreated

Naphtha

Xylene

Isomerization

Catalytic

Reformer

C5

Xyle

ne C

olu

mn

C9+

Refo

rmate

Split

ter

Dehepta

niz

er

Paraxylene

Recovery

Aromatics Generation

Aromatics

Extraction

Toluene

Conversion

Benzene C

olu

mn

Tolu

ene C

olu

mn

Xyle

ne C

olu

mn


C9+

Paraxylene

Hydrotreated

Naphtha

Xylene

Isomerization

Catalytic

Reformer

C5

Xyle

ne C

olu

mn

C9+

Refo

rmate

Split

ter

Dehepta

niz

er

Paraxylene

Recovery

Benzene/Toluene Purification

Aromatics

Extraction

Toluene

Conversion

Benzene C

olu

mn

Tolu

ene C

olu

mn

Xyle

ne C

olu

mn


C9+

Paraxylene

Hydrotreated

Naphtha

Xylene

Isomerization

Catalytic

Reformer

C5

Xyle

ne C

olu

mn

C9+

Refo

rmate

Split

ter

Dehepta

niz

er

Paraxylene

Recovery

Paraxylene Recovery

Aromatics

Extraction

Toluene

Conversion

Benzene C

olu

mn

Tolu

ene C

olu

mn

Xyle

ne C

olu

mn


C9+

Paraxylene

Hydrotreated

Naphtha

Xylene

Isomerization

Catalytic

Reformer

C5

Xyle

ne C

olu

mn

C9+

Refo

rmate

Split

ter

Dehepta

niz

er

Paraxylene

Recovery

Isomerize M-Xylene and O-Xylene into PX

Aromatics

Extraction

Toluene

Conversion

Benzene C

olu

mn

Tolu

ene C

olu

mn

Xyle

ne C

olu

mn


C9+

Paraxylene

Hydrotreated

Naphtha

Xylene

Isomerization

Catalytic

Reformer

C5

Xyle

ne C

olu

mn

C9+

Refo

rmate

Split

ter

Dehepta

niz

er

Paraxylene

Recovery

Transalkylation / Disproportionation

Limitation for PX from Reformate –

Methyl Group Shortage

Aromatics derived from reformate has a shortage of methyl groups

to maximize PX

Typical in

Reformate

(wt%)

Required to make PXMethyl Group

Shortage

Benzene 10 Two methyl group addition 2

Toluene 29 One methyl group addition 1

Ethylbenzene 6Ethyl group converting into

two methyl group 0 or 2

Mixed Xylenes 28 Purification and isomerization 0

C9+ Aromatics 12C2+ alkyl group removal and

methyl group transalkylation-0.5

• Toluene disproportionation (TDP)

• Toluene transalkylation

(TA) with C9+

Transalkylation simply shifts methyl groups from one aromatic to another

Transalkylation Technology

By-product benzene is inevitable due to imbalance of methyl groups in the feed

CH3

2

++

+

CH3

CH3

CH3CH3

CH3

CH3CH3

CH3

CH3

CH3

+

CH3CH3

C2H5

+

CH3

CH3

+ gas

Yield Pattern of Toluene/A9/A10

Transalkylation

Transalkylation rearranges the

methyl groups.

To maximize PX, methyl groups

must be added.Benzene

Toluene

Xylenes

TriMB

TetraMB

Equilibrium Distribution of methyl substituted aromatics

Methyl/Phenyl ratio in Feed

Reformate Feed

Eq

uil

ibri

um

Co

nc

en

tra

tio

n, m

ol.

%

Goal for Xylenes = 2.0

• A significant portion of world benzene supply is from co-product of PX

manufacture.

• Benzene periodically goes into oversupply due to market reasons; and

is in chronic oversupply on a regional basis.

• TDP, STDP, and transalkylation yield by-product benzene due to

deficiency of methyl groups.

Benzene – Not an On-Purpose Product

Benzene pricing is volatile, and sometimes low

Benzene

1000-1500 USD/MT

• Maximize the value among benzene, toluene, mixed xylenes, PX

• Make petrochemicals, not fuels

• PX for polyester is the goal

Need to Lower Feedstock Cost,

and Optimize the Product Mix

Benzene Toluene/A9/A10 Paraxylene

1000-1150 USD/MT 1250-1400 USD/MT1000-1500 USD/MT

CH3 CH3

CH3

Supporting price for

BTX is crude oil

• Methyl group addition is the only way to counter the lower yield of

xylenes. This is done by alkylating low-cost methanol.

Molecule Management with New Feedstock

Benzene Toluene/A9/A10 Paraxylene

1000-1150 USD/MT 1250-1400 USD/MT1000-1500 USD/MT

CH3 CH3

CH3

Supporting price for

methanol is natural gas

C–O

H HH

H

Methanol 200-400 USD/MT

“If I were a chemist . . . . .”

• Conventional PX

technologies utilize

existing molecules.

• Chemists synthesize

new molecules by

adding individual parts.

How do you integrate new methods, with

traditional production techniques?

The Magic Number is “8” (Carbons)

Only Toluene Methylation adds

molecules

• Hydrodealkylation subtracts methyl

groups

• Isomerization neither adds or subtracts

• Transalkylation shifts surplus methyl

groups to other molecules, and removes

ethyl groups and higher

GT-TolAlk

Methyl Group Management

Hydrodealkylation removes methyl groups to produce

on-purpose benzene. By-product is fuel gas.

Transalkylation and Isomerization re-arrange methyl

groups and remove higher alkyl groups.

Toluene Methylation adds methyl groups to produce

xylenes. By-product is water.

CH3

+ CH3OH

CH3

CH3

+ H2O

Post-fractionation

Reactor

Toluene

Separator C9+A to Transalkylation

MX to PX unitLight Ends

Recycle Toluene

Methanol

Waste Water

GT-TolAlk℠Process Scheme

Off Gas

Simple, fixed-bed design with no hydrogen compressor or circulation

Stabilizer

Typical Condition and Yields for TM

Condition

Catalyst ZSM-5 based

Temperature 450-550oC

Pressure 3 kg/cm2

H2O/HC 2/1

WHSV 4 hr-1

Toluene conversion (per pass) 0.20-0.35

Methanol utilization

(methyl group to aromatic ring) 86 wt%

Economics for GT-TolAlk℠

Basis: 400 KTA Toluene / 2013 Raw Material and Product Prices (IHS)

Feedstock KTA Unit price, $/ton Annual $MM

Toluene 400 1140 456

Methanol 189 389 74

Feed Costs $530

Products

Fuel Gas 14 725 10

Mixed Xylenes 389 1320 513

A9 80 1130 91

Process Water 107 -10 -1

Products Value $ 613

Utilities 38

Net Margin $ 45

TIC (USGC, 2013,

reaction plus fractionation)$ 42

Simple ROI = 12 Months

GT-TolAlk℠, Drop-in to

Existing Aromatics Complex

Only paraxylene

is produced from

aromatic feed.

Summary

• Relative shortage of xylenes from traditional refinery sources; regional surplus

of benzene

• GT-TolAlk℠ replenishes the methyl group shortage to yield more xylenes

• Simple fixed-bed, low pressure process

• No hydrogen is needed

• Very low EB yield in the xylenes; debottlenecks adsorption separation systems

• Unique process system can convert 100% of aromatic molecules to PX with

zero benzene by-product; or maximize benzene production if market justifies

Cutting Edge Cutting Edge Processes

for PX Production

CrystPX℠ - low-cost efficient crystallization process for paraxylene production

AdsorbPX℠ - PX recovery by selective adsorption

GT-Hybrid PX℠ - Combination of adsorption plus crystallization for reliable,

low-cost PX manufacture in revamps and grassroots applications

GT-TolAlk℠ - PX manufacture from lower-cost raw materials, with no benzene

production

GT-BTX PluS℠ - Patented process to recover aromatics from FCC gasoline by

direct extraction

GT-Aromatization℠ - Aromatics created from C4-C8 olefins, LPG, and light

naphtha

GT- IsomPX℠ and GT-TransAlk℠ - Aromatics transformation using catalysts

from Clariant

Rethinking Xylenes Production via Toluene Methylation

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